All items in category Magazine Articles
R&D Stories: A DSP Audio Processor at the Heart
by Al Clark

R&D Stories: A DSP Audio Processor at the Heart

This article, written by Al Clark (CEO, Danville Signal Processing), tells the story of his company’s R&D journey into the development of the dspNexus DSP Audio Processor. An interesting perspective about how the author’s experience led him to maximize the possibilities of digital audio, resulting in successfully bringing to market a dedicated DSP audio processor that could be used as a control center, a preamplifier, and a DSP engine for powered loudspeaker applications. This article was originally published in audioXpress, November 2021.
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Patent Review: Virtual Height Filter for Reflected Sound Rendering Using Upward Firing Drivers
by James Croft

Patent Review: Virtual Height Filter for Reflected Sound Rendering Using Upward Firing Drivers

This review discusses a patent that applies to speakers designed for new immersive audio formats in home applications and Dolby Atmos, in particular. Not surprisingly, the patent was awarded to Dolby Laboratories Licensing Corp. As the patent was granted, Voice Coil provided an extensive and informative review - recommended reading for anyone considering entering this important home-theater market segment. This article was originally published in Voice Coil, February 2016.
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Fresh From the Bench: SPL Phonitor One d Headphone Amplifier System
by Stuart Yaniger

Fresh From the Bench: SPL Phonitor One d Headphone Amplifier System

Stuart Yaniger shares his impressions and measurements of the Phonitor One d Headphone Amplifier System, designed by SPL of Germany. This product uses the company’s unique 120V circuitry, and also features an acclaimed AKM premium USB DAC and balanced stereo line output, effectively enabling it to function as a combination DAC and preamp. An interesting design also because of its Phonitor Matrix, a unique feature designed to electronically create a crosstalk signal and generate something similar to the effect of acoustic crosstalk around our head when listening through headphones. This article was originally published in audioXpress, November 2021.
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Crosslite+ Two-Way DSP Filter Design Tutorial
by Vance Dickason

Crosslite+ Two-Way DSP Filter Design Tutorial

In this article, Vance Dickason highlights the possibilities for a two-way DSP filter design using the CrossLite+ software package. Under development by the Brazilian pro audio company since 2009, CrossLite+ is a dual-channel FFT analyzer that will function with basically any USB-type recording interface. CrossLite+ is intended primarily for product development of DSP-powered pro speakers and for use in live sound PA systems. And measured data can also be imported from other analyzers such as the CLIO or Klippel This article was originally published in Voice Coil, December 2021.
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Speaker Applications Using Alpine HX5 Ultra Strong Lightweight Nanocomposite
by Mike Klasco

Speaker Applications Using Alpine HX5 Ultra Strong Lightweight Nanocomposite

Loudspeaker designers can look forward to a couple of exciting materials that have been in stealth mode but are about to step into the spotlight. A lightweight military aviation-grade nanocomposite from Alpine Advanced Materials, HX5 may be an alternative to beryllium and high-performance aluminum alloys used in woofer, midrange, and full-range cones. Compared to aluminum, cones can be made at half the weight with comparable strength. This article was originally published in audioXpress, January 2022.
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Patent Review: Extended Duct with Damping for Improved Speaker Performance
by James Croft

Patent Review: Extended Duct with Damping for Improved Speaker Performance

This article reviews a patent granted to Apple, describing an electronic audio device including an enclosure having an acoustic output opening and a speaker positioned within the enclosure, as implemented in the company’s range of iMac desktop computers. The speaker and the acoustic output opening are acoustically coupled by an acoustic output pathway and damping chamber. Apple’s patent cites the Matsushita patent as prior art, but this is a more developed concept. This article was originally published in Voice Coil, December 2015.
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Fresh From the Bench: USound Megaclite 4.0 UH-R2040 MEMS Earphones
by Brent Butterworth

Fresh From the Bench: USound Megaclite 4.0 UH-R2040 MEMS Earphones

The Megaclite 4.0 UH-R2040 is a reference design based on USound's Achelous UT-P2018 MEMS drivers, comparable in length and width to smaller balanced armatures, but thinner. They’re SMT reflow-compatible, so easy to incorporate into automatic assembly processes. Brent Butterworth listened, measured, and compared the performance of this new design against conventional in-ear products using established driver technologies. This article was originally published in audioXpress, October 2021.
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Patent Review: Loudspeaker Having a Passive Radiator US9426548B2
by James Croft

Patent Review: Loudspeaker Having a Passive Radiator US9426548B2

This article discusses a very interesting design and patent granted in August 2015 to Gary A. Rayner and James C. Larsen, as the inventors, on behalf of Treefrong Developments, from San Diego, CA. The patent abstract details a loudspeaker using one or more active drivers, with a passive radiator connected to each driver and dedicated processors and amplifier per channel - a slightly different approach to a familiar concept. This article was originally published in Voice Coil, November 2015.
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R&D Stories: The Tetrahedral Test Chamber Story (Part 2) - Consistent Loudspeaker Measurements
by Geoff Hill

R&D Stories: The Tetrahedral Test Chamber Story (Part 2) - Consistent Loudspeaker Measurements

In this article Geoff Hill completes the Tetrahedral Test Chamber story, a concept born out of necessity, simple wavelength theory and Beranek's wedges, measurement theory, and building upon experience gained in designing chambers in Europe, US, and Asia. These chambers are now in use throughout the world, providing consistent, reliable, and accurate measurements of loudspeaker transducers and loudspeaker systems. This article was originally published in audioXpress, October 2021.
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R&D Stories: The Tetrahedral Test Chamber Story (Part 1) - Recognizing the Need for Consistent Measurements​
by Geoff Hill

R&D Stories: The Tetrahedral Test Chamber Story (Part 1) - Recognizing the Need for Consistent Measurements​

This article revisits the story of the development of the Tetrahedral Test Chamber (TTC), by Geoff Hill, loudspeaker engineer, author, and inventor, in an effort to solve the longstanding problem of making consistent loudspeaker measurements. This innovative loudspeaker test chamber is now defined in international standards and in use throughout the world, scalable to any size of loudspeaker driver. This article was originally published in audioXpress, September 2021.
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